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PubMed1994

Progestins in preventive hormone therapy. Including pharmacology of the new progestins, desogestrel, norgestimate, and gestodene: are there advantages?

Progestins have played an important role in hormone replacement therapy (HRT). This article reviews the history, structure, and pharmacology of synthetic progestins, including the new progestins, norgestimate, gestodene, and desogestrel. The benefits and potential effect on carcinoma of the breast for each HRT are summarized. Current treatment alternatives are addressed.

Breast Neoplasms↗
PubMedDate not supplied

Hemostatic effects of two oral contraceptives containing low doses of ethinyl estradiol and either gestodene or norgestimate: an open, randomized, parallel-group study.

OBJECTIVE: To determine effects on blood clotting of two modern low-dose monophasic oral contraceptives. SUBJECTS AND METHODS: We measured in vivo markers of intravascular coagulatory and fibrinolytic activity in 40 volunteers randomly assigned to one of two low-dose oral contraceptives (OCs) for 6 months; one contained 35 micrograms of ethinyl estradiol (EE) plus 250 micrograms of norgestimate and the other, 30 micrograms of EE plus 75 micrograms of gestodene. RESULTS: Both formulations increased coagulatory as well as fibrinolytic activity over baseline: circulating reactive products of thrombin increased by 40%, and plasmin activity by 60%, after 3 months of treatment. Six months of OC use increased hemostatic activity substantially over that with 3 months of use. Differences between both OC formulations were marginal and clinically insignificant. CONCLUSION: The data suggest an EE-dose-dependent, balanced activation of in vivo coagulation and fibrinolysis in users of currently available, combined OCs. However, there is considerable consumption of coagulation inhibiting factors, suggesting that women with congenital deficiencies of antithrombin III and protein C should not use combined OCs.

Adult↗
PubMed1995

Norgestimate.

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Carbohydrate Metabolism↗
PubMed2004

Norgestimate and medroxyprogesterone acetate do not attenuate the atheroprotective effects of 17beta-estradiol in ovariectomized, apolipoprotein E-deficient mice.

OBJECTIVE: To determine whether progestins counteract the cardioprotective effects of estrogen. DESIGN: Controlled animal study. SETTING: Academic laboratory environment. ANIMAL(S): Female apolipoprotein E-deficient mice. INTERVENTION(S): Mice were randomly assigned to groups receiving a sham operation plus placebo pellet, bilateral gonadectomy plus placebo pellet, or gonadectomy plus one of nine combinations of estrogen/progestin SC pellets. MAIN OUTCOME MEASURE(S): Total plasma cholesterol, body weight, fat depot weight, uterine weight and size, and the cross-sectional area of fatty streaks in the aortic sinus were measured in each animal. RESULT(S): After 8 weeks of treatment, plasma cholesterol levels were significantly higher only in the ovariectomized and sham-operated animals that received placebo pellets. No differences in plasma cholesterol were observed relative to the type or amount of progestin administered. There was a reduction in fatty streaks in all of the hormone treatment groups as compared with both the ovariectomized and sham-operated animals that received placebo pellets. CONCLUSION(S): There were no significant differences in lesion area in response to estrogen alone or to estrogen plus the different types and doses of progestins.

Adipose Tissue↗
PubMedDate not supplied

Effect of a unique constant-estrogen, pulsed-progestin hormone replacement therapy containing 17beta-estradiol and norgestimate on endometrial histology.

OBJECTIVE: To evaluate the effect of a 17beta-estradiol(E2)/norgestimate (NGM) HRT regimen, which provides constant estrogen in combination with pulsed progestin administration, on endometrial histology in healthy postmenopausal women 40 to 65 years of age who had experienced natural menopause at least 12 months before the start of the study. METHODS: A total of 1,253 postmenopausal women were randomized to receive either continuous 1 mg E2, or constant estrogen, pulsed progestin regimens of 1 mg E2/30 microg NGM, 1 mg E2/90 microg NGM, or 1 mg E2/180 microg NGM (3 days on, 3 days off) in a 12-month, multicenter, double-blind study. Endometrial biopsies were obtained pre- and post-treatment, and were evaluated by at least 2 (if required, by 3) pathologists who were blinded with respect to treatment and to each other's diagnosis. RESULTS: At the end of the study, no cases of endometrial hyperplasia were diagnosed in subjects who received E2 1 mg/NGM 90 microg or E21 mg/NGM 180 microg, whereas 74 (28%) and 16 (6%) cases of endometrial hyperplasia were diagnosed in subjects who received continuous E2 1 mg and E2 1 mg/NGM 30 microg, respectively. A dose-related endometrial response to NGM was apparent (P < .001). The percentage of patients with inactive/atrophic endometrium increased with NGM dose. CONCLUSION: The results of this study support the safety and efficacy of this unique HRT regimen and suggest that the minimal NGM dose required to protect the endometrium from hyperplasia in a pulsed progestin regimen consisting of continuous E2 1 mg is 90 microg.

Adult↗
PubMed1990

The selectivity of a new progestin.

Norgestimate is a new progestin developed for use with ethinyl estradiol as a combination oral contraceptive. It binds to rabbit uterine progestational receptors and in the oral form stimulates a progestational endometrial effect in rabbits. Norgestimate also exerts a direct effect on target organs, stimulating the endometrium in rabbits when injected directly into the uterine horn and inhibiting luteinizing hormone release from rat pituitary cells in culture. Like other progestins, norgestimate inhibits ovulation in several species and estrogen-induced vaginal cornification in ovariectomized rats, but it is not estrogenic. Unlike other progestins, including levonorgestrel and gestodene, norgestimate is relatively free of androgenic activity. Norgestimate's affinity for the androgen receptor is very poor (0.003 x dihydrotestosterone [DHT]), even poorer than that of progesterone (0.005 x DHT). In sharp contrast are the marked affinities of levonorgestrel (0.220 x DHT) and gestodene (0.154 x DHT) for that receptor. The selectivity of norgestimate at receptor level is demonstrated clearly by its highly favorable androgen-to-progestin binding ratio. Norgestimate is similar to progesterone in not significantly stimulating ventral prostate growth in immature rats, whereas levonorgestrel, gestodene, and desogestrel are significantly androgenic in this model. Further evidence of norgestimate's minimal androgenicity is its lack of affinity for human sex hormone binding globulin in vitro. In conclusion, these preclinical studies, consistent with clinical studies, demonstrate the progestational efficacy and selectivity of norgestimate.

Animals↗
PubMed1996

The increased risk of venous thromboembolism and the use of third generation progestagens: role of bias in observational research. The Transnational Research Group on Oral Contraceptives and the Health of Young Women.

A matched case-control study was undertaken in 10 centers in Germany and the United Kingdom to explore the association of current use of major combination oral contraceptives with the occurrence of venous thromboembolism. The cases recruited were 505 women aged 16-44 years with venous thromboembolism, controls were 1877 women (at least 3 controls per case) matched for 5-year age group and region without VTE. The main outcome measures were odds ratios derived by comparing current use of a specific oral contraceptive or group of OC against current use of other groups or against no current use of OC. The odds ratios (95% confidence intervals) for venous thromboembolism were: for third generation products (low dose ethinyloestradiol, gestodene and desogestrel) versus second generation products (low dose ethinyloestradiol, no gestodene and desogestrel, 1.5 (1.1 to 2.0), for third versus second generation products with norgestimate included in third generation, 1.6 (1.2 to 2.2). The odds ratios for current use for women aged 16-44 of specific progestagens versus levonorgestrel-containing compounds were 1.7 (1.1 to 2.6) for gestodene, 1.8 (1.2 to 2.6) for desogestrel, 1.9 (1.0 to 3.6) for norgestimate and 1.3 (0.7 to 2.5) for progestagen-only pills. For women aged 25 to 44 likely to be exposed to any of these progestagens, odds ratios for the comparison of progestagens versus levonorgestrel showed a successive increase by market introduction ranging from 1.5 (0.9 to 2.5) for desogestrel with 30 micrograms oestrogen content (introduced 1981) to 2.8 (1.3 to 6.5) for desogestrel with 20 micrograms oestrogen content (introduced 1992) significant in linear trend analysis (p = 0.00012). The influence of norgestimate classification as third or second generation product does not significantly alter the results regarding the association of third generation products and venous thromboembolism. A direct comparison of current use of norgestimate (which is primarily metabolized to levonorgestrel) versus levonorgestrel shows an increased odds ratio. The trend of increasing risk of progestagens by recency of market introduction when compared with levonorgestrel is strongly indicative of the existence of external bias due to attrition of susceptibles.

Adolescent↗
PubMed1990

Intermittent GnRH antagonist plus progestin contraception conserving tonic ovarian estrogen secretion and reducing progestin exposure.

The present study was designed to evaluate the effectiveness of a once-weekly regimen of GnRH antagonist followed by a progestin as a potential new contraceptive method. On menstrual cycle days 2, 9, 16, and 23 (onset of menses = Day 1) monkeys were divided into two groups: 1) those injected sc with 0.1 mg/kg Nal-Glu GnRH antagonist in saline and those given only vehicle (control). On cycle days 15 to 26, each treated female was administered 25 micrograms norgestimate/day orally. This was continued for three treatment cycles (84 days). Weekly injections of Nal-Glu GnRH antagonist effectively blocked completion of folliculogenesis, ovulation, and corpus luteum function as judged by serum LH, E2, and P levels. Serum progesterone was undetectable (less than 0.1 ng/ml) during the treatment cycles. Importantly, serum estradiol levels during GnRH antagonist plus norgestimate treatments were maintained at 35 +/- 7 pg/ml. Upon the cessation of norgestimate treatment on day 26 in each cycle, menses uniformly began within 2 or 3 days. Regarding recovery, apparently normal and presumably ovulatory menstrual cycles, as judged by timely estradiol elevations, midcycle LH surges, and luteal phase progesterone patterns, were manifest immediately following termination of the final GnRH antagonist plus norgestimate treatment cycle. Endometrial biopsies removed on day 26 of control cycles, and on day 26 of the third treatment cycle revealed appropriate late secretory phase endometrium having tortuous endometrial glands and superficial stromal edema. Histological sections of ovaries removed at the end of the GnRH antagonist plus norgestimate treatment revealed multiple small and medium-sized developing and atretic follicles, having maintained serial ablation of the potentially maturing follicles.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2001

Preclinical profiles of progestins used in formulations of oral contraceptives and hormone replacement therapy.

Progestins used in oral contraceptive formulations available in the United States include norgestimate, desogestrel, norethindrone, norethindrone acetate, and levonorgestrel. Progestins used in the United States in continuous and intermittent formulations of hormone replacement therapy are norgestimate, medroxyprogesterone acetate, and norethindrone acetate. The chemical structure of a progestin determines its relative binding affinity for the progesterone and androgen receptors, as well as the sex hormone binding globulin in human serum, and determines its clinical profile. Overall, the properties of levonorgestrel or norethindrone acetate in this regard differ from norgestimate and are more conducive to androgenic stimulation. Estrogen replacement offers cardioprotective effects in postmenopausal women. Progestins are added to hormone replacement therapy to counteract the well-known increased risk of endometrial hyperplasia associated with the use of unopposed estrogen. Animal models show that for some parameters, including improvement of lipid profiles, progestins can diminish the cardioprotective effect of estrogen. Initial animal studies of norgestimate combined with estrogen do not show an attenuation of estrogenic effects.

Animals↗
PubMed2005

Interaction of progestins with the human multidrug resistance-associated protein 2 (MRP2).

Progestins are widely used as oral contraceptives and hormone replacement therapy. Recently it has been demonstrated that many progestins are inhibitors of P-glycoprotein, possibly explaining gender differences in drug actions. In vitro evidence suggested that at least norgestimate might also inhibit other transporters like the multidrug resistance-associated protein 2 (MRP2). We therefore investigated whether norgestimate, desogestrel, medroxyprogesterone acetate, norethisterone, progesterone, cyproterone acetate, chlormadinone acetate, and levonorgestrel inhibit MRP2 in vitro using confocal laser scanning microscopy and 5-chloromethylfluorescein diacetate as a prodrug of the fluorescent 5-chloromethylfluorescein (CMF), which is actively transported by MRP2 as glutathione conjugate. Of the progestins tested, only norgestimate (50 microM) and progesterone (100 microM) significantly increased intracellular CMF fluorescence by 62% and 53%, respectively. In conclusion, the progestins norgestimate and progesterone significantly inhibit the transport activity of MRP2 in vitro.

ATP Binding Cassette Transporter, Subfamily B↗
PubMed1995

Gestodene. A review of its pharmacology, efficacy and tolerability in combined contraceptive preparations.

The newer progestogens gestodene, desogestrel and norgestimate were developed in an attempt to produce agents with more selective progestational activity that would improve cycle control and minimise metabolic changes and adverse events while effectively preventing pregnancy. In clinical practice, gestodene is combined with ethinylestradiol in monophasic or triphasic combined oral contraceptive preparations. The drug has pharmacokinetic advantages over the other new progestogens in that it is active per se (the others are prodrugs) and has high bioavailability (approximately 100%). The ability of gestodene-containing oral contraceptives to inhibit ovulation is similar to that of preparations containing other progestogens although the required dosage is lower. In common with oral contraceptives containing desogestrel or norgestimate, and in contrast with those containing levonorgestrel, gestodene-containing preparations are associated with neutral or positive changes in lipid and carbohydrate metabolism. The effects of gestodene preparations on coagulation parameters, like those of desogestrel and levonorgestrel, are balanced by changes in the fibrinolytic system. Although the impact of these changes on clinical cardiovascular end-points has not been determined, the altered lipid profile is not likely to have significant clinical relevance because of the predominantly thrombogenic nature of cardiovascular disease in oral contraceptive users. Pregnancy rates and Pearl Indices with gestodene-containing preparations are low and similar to those with preparations containing other progestogens. Most pregnancies are attributable to user failure. Cycle control appears to be better with gestodene preparations than with levonorgestrel preparations, and available data suggest that cycle control may also be better with monophasic gestodene/ethinylestradiol than with monophasic desogestrel- or norgestimate-containing preparations, and better with triphasic gestodene- than with triphasic levonorgestrel- or norgestimate-containing preparations. However, differences between the new progestogen-containing preparations need to be confirmed in further large-scale trials. The most common adverse events with gestodene/ethinylestradiol are headaches and breast tension; the incidence of short term adverse events, including acne, is similar to that with preparations containing other progestogens. Changes in blood pressure and bodyweight are negligible. There are no comparative data on the incidence of cardiovascular events with gestodene-containing and other combined preparations. While the risk of breast cancer appears to be increased with long term combined oral contraceptive use in certain patient subgroups, this risk needs to be balanced against the noncontraceptive benefits of these preparations.(ABSTRACT TRUNCATED AT 400 WORDS)

Absorption↗